Get up and running in a minute
Lumi is an AI video learning companion for Chrome and Edge. Open any YouTube or Bilibili video to get live bilingual subtitles right on the player and a learning panel on the right for transcript search, AI chapter summaries, readable articles, and timestamped Q&A.
Install the extension & set your languages
Add Lumi from the Chrome Web Store or Edge Add-ons and pin it to your browser toolbar. Open any YouTube or Bilibili video and the learning panel will appear beside the player. Choose your interface language and target translation language on first launch — viewing subtitles, searching lines, and customizing caption styles all work without signing in.
Go to downloadsWatch a video that has no captions
When a video already includes native or auto-generated captions, Lumi uses them immediately for smart resegmentation and bilingual translation. For raw videos without any captions, run AI speech-to-text (ASR) to generate a timed transcript first — then translate, summarize, ask questions, or export the result as an SRT file.
View ASR duration packsUse Lumi AI out of the box, or bring your own API key
You can switch between both anytime. Sign in to use managed Lumi AI with zero setup (free accounts include 200,000 welcome Tokens plus a 7-day Lite Pro trial). Prefer your own provider? Enter your DeepSeek, OpenAI-compatible, Anthropic Claude, Gemini, or Paraformer key in extension settings and pay zero Lumi platform quota.
Sign in to LumiTop up or switch when your quota runs low
When your free balance runs out, upgrade to Pro (10,000,000 Tokens/month), grab an on-demand Token or ASR pack, or switch to your own API key.
Check my quotaAsk questions while watching and jump straight to the source
Whenever a concept or argument is unclear, ask in the AI chat tab right beside the video. Lumi grounds its answers in the transcript and attaches clickable timestamps — just like chapter summaries and article paragraphs — so one click jumps the player back to the exact sentence without opening a new tab.
Pick up where you left off & search your library
When signed in, your recent watch progress syncs automatically to the web Study Home. Save important lectures and talks to your personal Library so you can search across videos and ask questions later. When signed out, all progress stays locally in your current browser.
Open my libraryGet the latest Edge release without waiting for store review
Microsoft Edge Add-ons review can occasionally lag behind our latest release. You can download the official offline ZIP package from our website and load it in Developer Mode for the exact same features. If you already installed the Edge store version, disable it first so you don't see two Lumi panels.
Manual Edge install guideProvider configuration & quota
| Provider | Capabilities | Get an API key | Lumi quota | Shared ASR transcripts |
|---|---|---|---|---|
| DeepSeek | Text generation, subtitle translation and refinement, video summaries and chat, page translation | DeepSeek | 0 Tokens; provider bills separately | Local only: text BYOK runs privately and never enters the shared artifact pool |
| OpenAI / compatible API | Text generation, subtitle translation and refinement, video summaries and chat, page translation | OpenAI / compatible API | 0 Tokens; provider bills separately | Local only: text BYOK runs privately and never enters the shared artifact pool |
| Anthropic Claude / compatible API | Text generation, subtitle translation and refinement, video summaries and chat, page translation | Anthropic Claude / compatible API | 0 Tokens; provider bills separately | Local only: text BYOK runs privately and never enters the shared artifact pool |
| Aliyun Paraformer / DashScope ASR | Speech recognition for videos without subtitles | Aliyun Paraformer / DashScope ASR | 0 Tokens; provider bills separately | Complete transcripts passing audio identity checks may contribute; cross-account reuse requires Pro |
| Doubao Seed Flash ASR | Speech recognition for videos without subtitles | Doubao Seed Flash ASR | 0 Tokens; provider bills separately | Complete transcripts passing audio identity checks may contribute; cross-account reuse requires Pro |
| Item | AI Tokens |
|---|---|
| Free | 200,000 |
| Pro | 10,000,000 |
| BYOK Override / Shared AI Artifact | 0 |
Free accounts receive 200,000 tokens once, and Pro receives 10,000,000 tokens each calendar month. Pro tokens reset monthly; token pack balances last until used.
Setup steps
- Open extension settings and select your preferred AI model or speech-recognition provider.
- Paste your provider API key; for OpenAI- or Anthropic-compatible endpoints, confirm the Base URL and model name.
- Save and test the connection, then select that BYOK provider in the feature panel to start using it immediately.
API keys are stored locally inside your browser extension and are never included in cloud preference sync. Model availability, rate limits, and billing are managed directly by your chosen provider.
FAQ
- Which languages does Lumi support?
- The interface is available in Simplified Chinese, Traditional Chinese, English, Japanese, and Korean, and subtitle/page translation covers all major study and technical languages.
- Do I need a paid subscription to use Lumi?
- No. Bilingual subtitles, transcript search, caption styling, and Microsoft/Google page translation are free forever. For AI features, you can use your 200,000 free welcome Tokens, connect your own API key for free, or upgrade to Pro.
- Are my watch history and API keys private?
- Yes. Your BYOK API keys stay strictly inside your local browser extension and are never uploaded. Signing in only syncs the watch history and preferences needed to continue learning across devices — we never sell your data or use it for ads.